#include <iostream>
using namespace std;

int main(){
	string s1="",s2="Rong";
	string s3;
	s3=string(s2,0,2);
	cout << string::npos <<endl;
	cout << s1.end()-s1.begin() << endl;
	cout << s2.end()-s2.begin() << endl;
	cout << s3 <<endl;
	return 0;
}

